[WIP] add Makefile target to initialize the database (bug 1069388)

Fixes [bug 1069388](https://bugzilla.mozilla.org/show_bug.cgi?id=1069388)

Needs the https://github.com/mozilla/schematic/pull/1 PR merged in a branch
named "fake" for the requirements update to work.
Why not `loaddata initial.json` so that every `initial.json` file in any app will be loaded?